CONN 

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43 

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no.l82 


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in  2011  witii  funding  from 

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CONNECTICUT 


Agricultural  Experiment  Station 


NEW  HAVEN,  CONN* 


BULLETIN   182,  MARCH,    1914. 


ENTOMOLOGICAL  SERIES,  No.  20. 


Cbe  Brown^Cail  motb* 


r*-; 


0^%!^ 


Fig.  1.     Female  Brown-Tail  Moth.     Natural  size. 


CONTENTS. 


Page 


Officers  and  Staff 

The  Brown-Tail  Moth 

Status  of  the  Moth  Abroad,     . 
Appearance  and  Distribution  in  Amer- 
ica,   

Discovery  and  Spread  in  Conn.,     . 

Injury  to  Vegetation 

Food  Plants 

Danger  to  Health 

Means  of  Spread 


Life  History  and  Habits, 

Description, 

Native  Parasites  and  Other  Enemies, 

Imported  Parasites 

Control  Measures 

Removing  Winter  Nests, 

Spraying, 

Local  or  Community  Effort,    . 
Legislation  Needed  in  Conn,, 
Summary 


Page 

12 
15 
18 
19 
21 
22 
24 
24 
24 
25 


The  Bulletins  of  this  Station  are  mailed  free  to  citizens  of  Connecti- 
cut who  apply  for  them,  and  to  others  as  far  as  the  editions  permit. 


CONNECTICUT  AGRICULTURAL  EXPERIMENT  STATION. 


OFKICERS   AMD  STAKK. 


BOARD  OF  CONTROL. 

His  Excellency,  Simeon  E.  Baldwin,  ex-offlcio,  President. 

Prof.  H.  W.  Conn,  Vice  President Middletown 

George  A.  Hopson,  Secretary Wallingford 

E.  H.  Jenkins,  Director  and  Treasurer New  Haven 

Joseph  W.  Alsop  Avon 

Wilson  H.  Lee   Orange 

Frank  H.  Stadtmueller   Elmwood 

James  H.  Webb  Hamden 


Administration.  E.  H.  Jenkins.  Ph.D.,  Director  and  Treasurer. 

Miss  V.  E.  Cole,  Librarian  and  Stenographer. 
Miss  L.  M.  Brautlecht,  Bookkeepe'  and  Stenographer. 
William   Veitch,   In  charge   of  Buildings  and   Grounds^ 

Chemistry. 

Analytical  Laboratory.  John  Phillips  Street,  M.S.,  Chemist  in  Charge. 
E.  Monroe  Bailey,  Ph.D.,  C.  B.  Morison,  B.S., 
C.  E.  Shepard,  G.  L.  Davis,  Assistants. 
Hugo  Lange,  Laboratory  Helper. 
V.  L.  Churchill,  Sampling  Agent. 
Miss  E.  B.  Whittlesey,  Stenographer. 


Proteid  Research. 


T.  B.  Osborne,  Ph.D.,  Chemist  in  Charge. 
Miss  E.  L.  Ferry,  M.S.,  Assistant. 


Botany. 


G.  P.  Clinton,  S.D.,  Botanist. 
E.  M.   Stoddard,  B.S.,  Assistant. 
Miss  M.  H.  Jagger,  Seed  Analyst. 
Miss  E.  B.  Whittlesey,  Herbarium  Assistant. 


Entomology. 


W.  E.  Britton,  Ph.D..  Eniomdtogtst ;    SiatelEntomologisi. 
B.  H.  Walden,  B.Agr.,  First  Assistant. 
Q.  S.  Lowry.  B.S.,  I.  W.  Davis,  B.S.,  Assistants. 
Miss  F.  M.  Valentine,  Stenographer. 


Forestry. 


Walter  O.  Filley,  Forester;  also  State 

Forester  and  State  Forest  Fire  Warden. 
A.  E.  Moss,  M.F.,  Assistant  Station  Forester. 
Miss  E.  L.  Avery,  Stenographer. 


Plant  Breeding. 


H.  K.  Hayes,  M.S.,  Plant  Breeder. 
C.  D.  Hubbell,  Assistant, 


THE  BROWN-TAIL  MOTH 

Euproctis  chrysorrhoea  Linn. 
By  W.  E.  Britton,  State  Entomologist. 

The  brown-tail  moth  was  found  in  Thompson  in  1910  and 
is  now  present  throughout  the  northeastern  portion  of  Connec- 
ticut, about  one-third  of  the  area  of  the  state  being  infested. 
Though  the  pest  has  not  as  yet  become  sufficiently  abundant 
generally  to  cause  noticeable  injury,  it  is  spreading  gradually 
and  will  soon  infest  the  entire  state.  During  each  of  the  last 
three  years,  scouts  employed  by  the  writer  have  cut  off  and 
destroyed  the  winter  nests.  Had  this  not  been  done  consider- 
able damage  would  doubtless  have  resulted  in  Thompson, 
Putnam,  Pomfret  and  Woodstock,  where  the  nests  were 
thickest. 

Several  articles  relating  to  the  insect  have  appeared  in  the 
reports  and  bulletins  of  this  Station  during  the  past  few  years, 
but  they  are  now  inadequate  and  the  purpose  of  this  bulletin 
is  to  give  a  brief  account  of  the  brown-tail  moth,  its 
distribution  and  spread  up  to  the  present  time,  and  to  point 
out  the  best  methods  of  control.  The  illustrations  will  enable 
one  to  recognize  the  insect  iw  its  different  stages. 

Status  of  the  Moth  Abroad. 

The  brown-tail  moth  is  a  native  of  the  Old  World  where  it 
is  found  from  Algiers  on  the  South  to  Sweden  on  the  North 
and  from  England  on  the  West  to  the  Himalaya  Mountains  on 
the  East.  Over  most  of  this  area  it  is  recognized  as  a  pest 
of  orchards  and  forests.  At  more  or  less  regular  intervals 
there  are  outbreaks  of  this  insect,  resulting  in  severe  damage 
and  often  the  trees  are  stripped  on  large  areas. 

Dr.  L.  O.  Howard,*  in  1909,  found  this  insect  present  in  in- 

*Bureau  of  Entomology,  Bull.  87,  p.  21,  1910. 


4  CONNFXTICUT    ExPERIMKN'T    STATION,    BULLETIN      182. 

jurious  numbers  in  certain  parts  of  Europe,  especially  in 
France.  The  same  year  Mr.  H.  L.  Frost*  of  Arlington, 
Mass.,  found  that  the  Thiergarten  in  Berlin  had  been  closed 
to  the  public  on  account  of  the  serious  poisoning  of  people 
by  hairs  from  the  caterpillars,  which  were  ver}-  abundant. 

Appearance  and  Distribution  in  America. 

From  the  best  information  obtainable  it  appears  that  the 
brown-tail  moth  was  accidentally  introduced  into  this  country 
on  nursery  stock  at  Somerville,  Mass.,  more  than  twenty 
years  ago.  It  was  first  brought  to  the  attention  of  entomol- 
ogists in  1897,  when  it  was  identified  as  the  brown-tail  moth, 
and  a  special  bulletin  was  at  once  issued  by  the  Massachu- 
setts Agricultural  Experiment  Station  giving  information 
about  the  insect.  About  a  dozen  towns  were  then  known  to 
be  infested  and  the  Massachusetts  legislature  passed  a  law  re- 
quiring local  authorities  to  suppress  the  brown-tail  moths. 
This  law  is  still  in  force.  (In  1898,  $10,000  was  made  available 
for  the  control  of  this  insect,  and  the  work  was  placed  under 
the  Board  of  Agriculture. 

By  this  time  the  insect  had  already  become  firmly  establish- 
ed and  soon  spread  to  adjacent  territory.  In  December  1899, 
the  first  nest  was  found  in  New  Hampshire  at  Seabrook;  in 
the  spring  of  1904  many  pear  trees  at  Kittery,  Me.,  were  found 
to  be  infested ;  during  the  fall  of  1906,  the  brown-tail  moth  was 
reported  at  Pawtucket,  East  Providence  and  Woonsocket  in 
Rhode  Island.  On  April  6th,  1910,  winter  nests  were  received 
at  this  office  from  Mr.  Richard  Barton  of  Thompson,  Conn., 
who  stated  that  they  were  found  by  men  employed  by  Mr.  H. 
L.  Frost  in  pruning  trees  in  that  locality.  This  is  the  first 
record  of  the  establishment  of  the  insect  in  Connecticut,  and 
was  published  in  the  report  of  this  Station  for  1910,  page  683. 
In  August  1911  the  first  brown-tail  moths  were  found  in 
Vermont  at  Guilford. 

Meantime  the  brown-tail  moth  had  been  spreading  westward 
in  Massachusetts  to  the  Connecticut  River  Valley,  and  a 
separate  infestation  had  been  discovered  in  North  Adams. 

*Ibid. 


Discovery  and  Spread  in  Connecticut.  5 

At  the  present  writing,  February,  1914,  the  brown-tail  moth 
has  spread  over  the  following  territory :  the  southern  part  of 
Maine  and  about  3000  square  miles  of  Nova  Scotia,  and  6000 
square  miles  in  New  Brunswick ;  the  whole  of  New  Hampshire 
except  possibly  a  few  of  the  northern-most  towns  of  the  state, 
in  upper  Coos  county;  the  western  half  of  Vermont,  except 
possibly  a  few  towns  in  Essex  and  Orleans  counties  along  the 
northern  border;  nearly  all  of  Massachusetts,  except  a  part 
of  Berkshire  county,  and  possibly  a  few  adjoining  towns; 
the  whole  of  Rhode  Island;  about  one-third  of  Connecticut 
including  Windham  and  Tolland  counties  and  a  portion  of 
Hartford  and  New  London  counties ;  and  this  winter,  nests 
have  been  found  on  Fishers  Island,  which  belongs  to  the 
State  of  New  York. 

From  the  foregoing  paragraphs  it  will  be  seen  that  the 
pest  has  spread  muc^h  more  rapidly  and  now  extends  farther 
toward  the  north  and  east  than  toward  the  south  and  west. 
Though  the  climatic  conditions  may  be  slightly  more  favorable 
in  that  direction,  the  chief  reason  is  probably  due  to  the  pre- 
vailing winds,  which  in  summer  blow  northeastward.* 

Discovery  and  Spread  in  Connecticut. 

For  a  period  covering  several  years,  occasional  reports  ap- 
peared in  the  newspapers,  or  in  correspondence  regarding 
the  presence  of  brown-tail  moths  in  certain  places  in  the 
state.  These  reports  were  investigated  by  this  department, 
and  as  a  rule  it  proved  that  some  other  common  insect  had 
been  mistaken  for  the  brown-tail  moth,  and  the  reports  were 
therefore  incorrect.  But  on  April  6th,  1910,  the  following 
letter  was  received  from  Mr.  Richard  Barton  of  Thompson, 
manager  of  the  large  place  of  Mr.  Norman  B.  Ream : 

Dear  Sir : — I  am  mailing  to  you  under  separate  cover  in  a  box  some 
caterpillars'  nests  found  near  the  highway  on  a  pear  tree  by  one  of 
Mr.  H.  L.  Frost's  men,  who  was  doing  some  pruning  in  this  village. 
He  thought  it  was  the  brown-tail,  and  so  I  took  them  and  carefully 
cynanided  them  and  sent  them  to  you  for  identification.  I  really  hope 
that  they  are  not  brown-tails,  as  we  have  not  yet  been  troubled  with 
them  in  this  section.  However,  if  you  find  that  they  are,  if  you  will 
kindly  let  me  know  at  once  I  will  see  what  I  can  do  to  have  a  search 
made  in  the  village  with  a  view  to  stamping  them  out. 


6  Connecticut  Experiment  Station,  Bulletin    182. 

It  proved  to  be  the  brown-tail  moth,  and  two  assistants, 
Messrs.  Walden  and  Champlain,  visited  Thompson  and 
hunted  for  nests  and  found  in  all  about  a  dozen.  On  May 
10th  of  that  year  they  sprayed  with  lead  arsenate  all  trees  from 
which  the  nests  were  cut. 


Fig.  2.     Pear  tree  at  Putnain  stripped  by  brown-tail  caterpillars. 
(Photo.  June  15,  1910.) 


In  June,  caterpillars  were  found  in  Putnam  by  Mr.  John 
H.  Osgood  and  submitted  to  Professor  G.  H.  Lamson,  Jr.,  of 
the  Agricultural  College,  Storrs,  who  sent  them  to  this  office. 
Mr.  Walden  visited  Putnam  and  Mr.  Osgood  showed  him  the 
trees,  some  of  which  were  nearly  defoliated.     (See  figure  2), 

The  following  winter,  Federal  scouts,  who  were  looking 
for   gypsy   moth    eggs,    reported    that   brown-iail    nests    were 


Discovery  and  Spread  in  Connecticut.  7 

rather  abundant  on  fruit  trees  in  the  yards  of  Putnam  and 
that  they  observed  them  also  in  Thompson  and  Pomfret. 

Consequently  early  in  1911,  a  gang  of  men  under  Mr. 
Donald  J.  Caffrey,  scouted  that  section  of  the  state  for  the 
purpose  of  destroying  the  nests  and  learning  the  extent  of  the 
infestation.  Five  towns  were  found  infested.  A  total  of  7,133 
nests  being  destroyed,  112  in  Thompson,  937  in  Woodstock, 
5,989  in  Putnam,  89  in  Pomfret  and  6  in  Killingly. 

In  this  work  only  the  open  country  was  examined,  and  the 
nests  removed  from  orchard  and  roadside  trees  and  from  the 
borders  of  the  woodland  within  reach.  To  examine  the  whole 
forest  area  and  to  remove  nests  from  the  tall  oaks  would 
require  a  sum  of  money  greatly  in  excess  of  our  appropriation, 
and  was  therefore  impracticable. 

In  September  1911  a  colored  placard  11  x  14  inches  in  size 
and  giving  illustrations  of  the  brown-tail  moth  and  informa- 
tion regarding  it,  was  issued  as  a  special  bulletin  of  the  Station. 
A  copy  was  sent  to  each  library,  grange  hall,  post  office  and 
railroad  station  in  Connecticut,  and  to  all  schools  desiring  it. 

The  following  winter  1911-1912,  the  territory  was  again 
searched  and  a  total  of  3,084  nests  were  found  in  nine  towns 
as  follows:  Thompson,  966;  Woodstock,  699;  Putnam,  1,260, 
(against  5,989  the  previous  year)  ;  Pomfret,  82;  Killingly,  27; 
Brooklyn,  35;  Sterling,  1;  Plainfield,  13;  and  Stafford,  1.  In 
May,  1912,  caterpillars  were  found  in  Norwich  by  Mr.  J.  E. 
Fanning.  Mr.  Caffrey  visited  the  place  and  found  that  only 
a  comparatively  small  area  between  two  streets  seemed  to  be 
infested,  and  had  all  the  trees  in  that  area  sprayed  with 
poison. 

In  1912-13,  a  nest  was  received  from  West  Hartford,  and 
the  scouts  examined  many  towns  beside  those  previously 
known  to  be  infested.  A  total  of  29  towns  were  found  infest- 
ed and  7,592  nests  were  destroyed.  On  account  of  the  infes- 
tation the  Federal  Horticultural  Board  established,  August 
1st,  1913,  a  quarantine.  No  nursery  stock  can  be  shipped  out  of 
the  infested  area  which  has  not  first  been  examined  before 
being  packed,  and  certified  by  a  Federal  inspector.  This  quar- 
antine will  probably  be  extended  from  time  to  time,  to  corre- 
spond with  the  territory  infested  by  the  brown-tail  moth. 


8  Connecticut  Experiment   Station,  Bulletin    182. 

The  location  of  these  towns  and  the  quarantine  Hne  are 
shown  by  the  shaded  area  on  the  map  in  figure  3. 

At  the  present  writing  the  scouts  are  at  work  and  they  have 
found  nests  in  Granby,  Columbia,  Lebanon,  Colchester,  Led- 
yard,  Groton,  New  London,  Waterford,  East  Lyme,  Old  Lyme 
and  Saybrook.  Other  towns  not  .shaded  on  the  map  will 
probably  be  found  infested.  Nests  have  recently  been  found 
on  Fishers  Island. 


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Fig.  3.     Map  showing  quarantine  line  and  distribution  of  brown-tail 
moth  in  Connecticut  in  1913. 


Injury  to  Vegetation. 

The  brown-tail  caterpillars  injure  trees  by  devouring  their 
leaves.  When  caterpillars  are  abundant  trees  are  often 
stripped,  thus  weakening  them  and  causing  considerable  injur)-. 
At  present  in  Connecticut,  outside  of  the  fruit  trees,  little 
injury  has  been  done,  but  in  Massachusetts  and  New  Hamp- 
shire the  infestation  is  greater  and  much  injury-  has  resulted. 
In  Europe,  also,  repeated  attacks  have  either  killed  the  forest 
trees  or  greatly  reduced  their  vitality  so  that  they  are  often 


Food   Plants.  9 

attacked  and  killed  by  borers.     Many  fruit  trees  in  Eastern 
Massachusetts  have  been  killed  by  the  caterpillars. 

Food  Plants. 

Fernald  and  Kirkland  gave  a  list*  of  about  eighty  species 
of  trees  and  plants  on  which  the  caterpillars  are  known  to  feed. 
The  pear  is  the  first  preference  of  the  caterpillars,  followed 
by  the  apple  and  the  stone  fruits.  Oaks,  maples  and  elms  are 
perhaps  the  chief  kinds  of  shade  and  forest  trees  liable  to  be 
injured.  As  the  gypsy  caterpillars  feed  upon  over  six  hun- 
dred different  kinds  of  plants,  it  will  be  seen  that  the  brown- 
tail  is  much  more  limited  in  regard  to  its  food  plants.  Pear, 
apple  and  oak  trees  are  stripped  by  the  brown-tail  caterpillars. 

Conifers  are  not  attacked  but  the  caterpillars  will  feed  upon 
most  of  the  deciduous  trees  as  well  as  many  shurbs,  vines 
and  herbs,  if  their  favorite  food  is  lacking. 

Danger  to  Health. 

The  hairs  of  the  caterpillars  are  barbed  and  brittle,  and 
break  off  easily.  When  they  come  in  contact  with  the  human 
skin,  they  cause  an  irritation  or  rash  which  is  quite  serious 
with  certain  persons.  The  worst  forms  of  rash  are  caused 
by  actual  contact  with  the  caterpillars,  but  the  broken  hairs 
which  blow  about  will  cause  the  milder  forms.  The  matter 
has  been  carefully  studied  by  Dr.  E.  E.  Tyzzer**  of  the  Har- 
vard Medical  School,  who  finds  in  these  hairs  a  definite  poison- 
ous principle  which  causes,  certain  changes  in  the  blood.  The 
long  hairs  do  not  seem  to  possess  this  quality,  but  the  short 
barbed  hairs  of  the  red  dorsal  tubercles  are  the  ones  chiefly 
responsible,  though  similar  hairs  occur  with  the  long  ones  on 
various  portions  of  the  caterpillar,  and  on  the  posterior  ex- 
tremity of  the  body  of  the  adult.  In  making  the  cocoon  the 
hairs  are  rubbed  from  the  caterpillar  and  woven  into  the  new 
structure,  and  those  from  the  adult  female  are  worked  into 
the  formation  of  the  egg-mass,  so  that  either  cocoon  or  egg- 
mass  may  produce  the  rash.     Such  hairs  are  doubtless  cast 

*The  Brown-Tail  Moth,  Mass.  Board  of  Agriculture,  p.  57.    1903. 
**Second  Annual  Report  of  the  Superintendent  for  Suppressing  the 
Gypsy  and  Brown-Tail  Moths,  p.  154.     1907. 


10 


Connecticut  Experiment   Station,  Bulletin    182. 


with  the  skin  when  the  caterpillars  molt,  and  are  often  rubbed 
or  broken  off  from  their  bodies  and  blown  about,  and  coming 
in  contact  with  the  skin  of  human  beings  cause  the  brown-tail 
rash. 


Fig.  4.  Brown-tail  moths  on  tree  and  electric  light  pole,  Lowell, 
Mass.,  1910.  (After  Burgess,  Bureau  of  Entomology,  U.  S. 
Dept.  of  Agriculture.) 


As  a  remedy  for  this  rash  Kirkland  recommends  the  follow- 
ing, which  should  be  well  shaken  together  and  rubbed 
thoroughly  upon  the  affected  parts : 

Carbolic  acid  Yz  drachm 

Zink  oxide Yi  ounce 

Lime  water 8  ounces 


Means  of  Spread.  11 

Means  of  Spread. 

It  is  chiefly  in  the  adult  stages  that  the  brown-tail  moth 
spreads  to  infest  new  territory.  The  moths  emerge  during 
the  first  half  of  July  and  both  sexes  fly  and  are  attracted  to 
lights.  They  may  often  be  seen  during  the  day  at  rest  on 
electric  light  and  trolley  poles  in  infested  towns  and  cities, 
as  shown  in  figure  4.  A  gale  at  this  time,  carries  large  num- 
bers of  moths  with  it  and  if  blowing  towards  uninfested  ter- 
ritory, the  pest  will  spread  several  miles  in  a  season.  Moths 
are  also  attracted  by  the  lights  in  vehicles,  railway  coaches  and 
trolley  cars  and  are  often  carried  long  distances,  and  no  doubt 
new  infestations  are  started  in  this  manner.  Thus  from 
July  4th  to  July  18th,  1912,  when  the  moths  were  flying,  Mr. 
D.  M.  Rogers,  who  was  then  in  charge  of  the  Federal  work 
in  Massachusetts,  stationed  two  men  at  Putnam,  Conn.,  to 
examine  all  trains  headed  westward  or  southward,  to  remove 
the  adult  brown-tail  moths,  and  75  moths  in  trains  and  around 
the  station  were  destroyed. 

Caterpillars  in  their  winter  nests  may  be  transported  on 
nursery  stock,  or  in  the  waste  often  used  as  packing  material, 
in  an  infested  region.  In  fact  the  first  nests  found  in  Connect- 
icut came  on  fruit  tree  seedlings  imported  in  1909  from  a 
French  nursery.  From  this  stock  52  nests  containing  living 
caterpillars  were  taken,  and  the  following  year  14  more  nests 
were  found.  Had  it  not  been  for  this  inspection  the  pest 
might  have  become  established  around  these  nurseries,  one 
of  which  was  in  the  southwest  corner  of  the  state,  and  some 
of  the  stock  might  have  been  shipped  elsewhere,  perhaps  to 
other  states. 

The  young  caterpillars,  like  gypsy  caterpillars,  canker  worms 
and  many  other  larvse,  spin  down  upon  cars  and  vehicles  or 
any  object  passing  beneath  the  trees  and  may  thus  be  carried. 
Nearly  full  grown  caterpillars,  especially  in  a  badly  infested 
center,  often  strip  their  trees  and  crawl  about  for  food.  If 
they  crawl  upon  a  trolley  car  or  other  vehicle  they  might  easily 
be  carried  some  distance. 

It  is  certain,  however,  that  most  of  the  spread  is  due  to  the 
flight  of  the  moths. 


12 


Connecticut  Experiment   Station,  Bulletin    182. 


Life  History  and  Habits. 

The  partially  grown,  though  yet  small  caterpillars  pass  the 
winter  in  silken  webs  or  nests  at  the  ends  of  the  twigs.  These 
nests  are  composed  of  leaves  and  silk,  are  from  two  to  four 
inches  long,  and  are  shown  in  figures  5,  and  6.  They  first 
occur  on  pear,  apple  and  wild  cherr}^  trees,  and  if  ver\-  abun- 
dant in  the  locality  attack  also  oaks  and  most  other  deciduous 
trees.     There  are  no  other  nests  that  need  be  mistaken  for 


Fig.  5.     Winter  nests  on  pear  tree. 


these,  though  many  Promethea  cocoons  (see  figure  7)  are  sent 
to  this  office  with  the  idea  that  it  is  the  nest  of  the  brown-tail 
moth. 

On  the  approach  of  the  warm  days  in  April  the  caterpillars 
emerge  and  begin  to  feed  upon  the  opening  buds.  They  molt 
three,  and  sometimes  four  times,  becoming  full  grown  about 
the  middle  of  June,  when  they  are  from  one  and  one-fourth 
to  one  and  one-half  inches  long,  and  appear  as  in  figure  8. 
Each  then  draws  together  a  few  leaves,  fastening  them  with 
silk  threads,  and  pupates  within  them.     It  is  common  to  find 


Fig.  6.     Winter  nests  cut  from  a  pear  tree  in  Hartford;  center  nest 
shows  old  egg-mass  on  leaf.     Natural  size. 


14 


Connecticut  Experiment  Station,  Bulletin    182. 


three,  four  or  more  pupre  in  a  bunch  of  leaves.  \\'hen  abun- 
dant the  caterpillars  will  also  transform  under  fence  rails 
rubbish  and  other  protected  places. 

The  cocoon  stage  lasts  from  fifteen  to  twenty  days  and  then 
the  moths  appear,  usually  during  the  first  half  of  July.  As 
a  rule  they  emerge  late  in  the  afternoon  and  are  ready  to  fly 
the  first  night.  Both  sexes  fly  and  are  strongly  attracted  by 
lights.     Figure  4  shows  the  moths  at  rest  on  an  electric  light 


Fig.  7.     Cocoon  of  Promethea  moth.     Natural  size. 


pole  in  Maiden,  Mass.  The  moths  begin  at  once  to  lay  eggs 
which  are  usually  found  in  elongated  reddish-brown  masses 
containing  from  200  to  400  eggs  each,  on  the  underside  of  a 
leaf  and  shown  in  figure  9.  The  white  females  may  often 
be  seen  with  folded  wings  laying  the  eggs  as  in  figure  10.  The 
egg-masses  var}^  greatly  in  size  and  shape  but  are  usually 
from  half  to  three-fourths  of  an  inch  loni;-  and  jx^rliaps  one- 
fourth  of  an  inch  broad. 


Description.  15 

Nearly  three  weeks  later,  or  about  the  first  of  August,  the 
eggs  hatch  and  the  young  caterpillars  at  first  feed  on  the  surface 
of  the  leaf  bearing  the  egg-cluster  causing  it  to  turn  brown 
as  if  scorched.  Later  they  go  to  other  leaves  for  food  and 
when  five  days  old  they  molt.  Early  in  September  they  begin 
to  make  the  web  or  nest  in  which  they  are  to  spend  the  winter. 
This  is  made  by  drawing  together  some  old  leaves,  usually  in- 
cluding that  bearing  the  old  egg-mass,  which  sometimes  shows 
on  the  outside  as  in  figure  6.  These  leaves  are  fastened  to  the 
twig  by  encasing  their  petioles  with  woven  silk  which  is  woven 
also  around  the  twig  so  that  it  cannot  be  torn  away.  Much  silk 
is  used  in  the  construction  of  the  nest  which  is  usually  at  or 
near  the  end  of  the  season's  growth.  The  nests  vary  greatly, 
however,  in  size  and  shape  depending  upon  their  location  and 
the  materials  available.  Probably  all  caterpillars  hatching 
from  the  same  egg-mass  usually  go  into  the  same  winter  nest, 
but  where  the  insect  is  abundant  and  there  are  five  egg-clust- 
ers on  a  single  leaf  as  the  writer  saw  in  New  Hampshire,  it 
seems  as  if  they  must  get  somewhat  mixed.  Possibly  in  such 
cases  several  colonies  unite  in  the  nest,  and  this  may  account 
for  the  unusually  large  nests  occasionally  found.  The  cater- 
pillars feed  for  a  time,  after  making  the  nest,  going  into  it 
when  not  feeding,  but  on  the  approach  of  cold  weather  they 
crowd  into  it  one  hundred  or  more  in  a  nest  and  close  the  open- 
ing, remaining  there  until  spring. 

Description. 

Egg.  The  eggs  are  spherical,  yellow  in  color  and  are 
laid  on  the  under  surface  of  a  leaf  in  elongated  clusters  from 
half  to  three-fourths  of  an  inch  long,  and  about  one-fourth  of 
an  inch  thick.  Such  an  egg  cluster  contains  from  200  to  400 
eggs  which  are  covered  with  the  reddish-brown  hairs  from  the 
body  of  the  moth.  Egg-masses  are  shown  in  figure  9.  Eggs 
are  deposited  during  the  first  half  of  July  and  hatch  in  about 
three  weeks  or  early  in  August. 

Caterpillar.  The   fully   grown   caterpillar   is    reddish- 

brown  in  color,  the  body  being  dark  brown  splashed  with 
light  brown  and  bearing  light  brown  hairs.  Beginning  with 
the  fourth  segment  each  segment  bears  a  pair  of  white  tufts. 


16 


Connecticut  Experiment   Station,  Bulletin    182. 


one  on  each  side.  These  show  both  dorsally  and  laterally,  and 
from  above  appear  as  two  broken  white  stripes.  They  disap- 
pear, however,  in  rubbed  specimens,  the  white  hairs  breaking 
off  readily.  On  each  of  the  ninth  and  tenth  segments  there 
is  a  small  coral  red  tubercle  bearing  poisonous  hairs.     Length 


Fig.  8.     Brown-tail  caterpillars.     Natural  size. 


Fig.  9.     Egg-mass  on  leaf.     Natural  size. 


one  and  one-quarter  to  one  and  one-halt  inches.  The  cater- 
pillar stage  lasts  from  August,  when  the  eggs  hatch,  until  the 
larva  becomes  full  grown  about  the  middle  of  the  following 
June.  During  this  time  it  molts  three,  and  sometimes  four, 
times.     The  caterpillars  are  shown  in  figure  8. 


Description. 


17 


Winter  Nest.  The  nest  is  constructed  by  the  cater- 
pillars when  they  are  about  one-fourth  of  an  inch  long,  usually 
in  the  month  of  September.  One  or  more  terminal  leaves 
are  folded  and  fastened  to  the  end  of  the  twig  with  gray  silk 
which  also  forms  the  greater  part  of  the  tissue  of  the  nest.  It 
is  very  strong  and  cannot  readily  be  torn.  The  old  egg-mass 
often  shows  on  the  outside  of  the  nest.  Though  usually  from 
two  to  four  inches  long  the  nests  vary  greatly  in  size  and  shape, 
and  are  frequently  reduced  to  almost  nothing,  or  are  somewhat 
larger  than  the  size  given  above,  probably  due  to  several  colo- 


FiG.  10.     Female  laying  eggs, 
slightly  enlarged. 


Fig.  11.     Coc'-ons  of  brown-tail 
moths.     Natural  size. 


nies  uniting  in  the  same  nest.     Nests  are  shown  in  figures  5 
and  6. 

Cocoon.  The  pupse  are  generally  clustered  together  in 
folded  leaves  and  fastened  with  loose  silk,  as  shown  in  figure 
11.  The  naked  pupa  is  about  half  an  inch  long,  and  less  than 
half  as  broad,  tapering  abruptly  toward  the  tail.  Color,  dark 
brown.  This  stage  lasts  from  fifteen  to  twenty  days,  depend- 
ing somewhat  upon  the  weather  conditions. 

Moth.  The  adult  is  pure  white  with  the  end  of  the  abdo- 
men  covered  with   reddish-brown  hairs.     In  the  male  there 


18  Connecticut  Experiment   Station,  Bulletin    182. 

is  a  brown  suffusion  along  the  front  margin  of  the  underside 
of  the  forewings  and  the  antennae  are  more  or  less  tinged  with 
brown.  In  size  there  is  a  variation  from  an  inch  to  an  inch 
and  a  half  in  wing-expanse,  the  females  being  larger  than  the 
males  and  having  thicker  bodies.  The  males  on  the  other 
hand  have  larger  antennae.  The  females  are  often  seen  with 
folded  wings  laying  eggs  as  in  figure  10.  Both  sexes  are 
shown  in  figure  12.  The  moths  fly  during  the  first  half  of  July 
and  are  attracted  by  lights. 


Fig.  12.     Brown-tail  moths.     Natural  size.     Female  at  left. 

Native  Parasites  and  Other  Enemies. 

In  certain  moist  seasons  a  natiAC  fungus  Entoiuopthora 
(Empusa)  aulicae  Reichardt  attacks  and  kills  many  small 
caterpillars  in  the  nests  and  likewise  the  larger  ones  in  early 
summer.  The  latter  die  on  the  trees  or  stones  of  buildings 
and  walls  and  remain  there  for  a  time  as  in  figure  13.  This 
disease  killed  millions  of  the  caterpillars  in  1906  in  Massachu- 
setts, and  occasionally  since  then  it  has  aided  in  holding  the 
pest  in  check.  Under  favorable  conditions  it  is  capable  of 
killing  sixty  per  cent,  or  more  of  the  caterpillars.  In  a  dry 
season,  however,  it  kills  few  caterpillars,  and  like  other 
fungous  diseases  of  insects,  does  the  most  elioctivc  work 
in  badly  infested  centers  where  the  caterinllars  arc  very  abun- 
dant and  are  crowded  together. 


Imported  Parasites. 


19 


A  few  native  insect  parasites  normally  attacking  related 
species  also  attack  the  brown-tail  moth  but  are  not  important 
in  checking  it.  Birds,  especially  the  cuckoos,  feed  upon  the 
caterpillars,  and  many  kinds  of  birds  devour  the  moths.  Even 
English  sparrows  were  seen  by  Mr.  Kirkland  to  feed  upon 
them  in  1897.  But  these  native  enemies  working  together 
are  not  effective  in  greatly  reducing  the  numbers  of  the  insects. 


Fig.  13.     Brown-tail  caterpillars  killed  by  fungous  disease. 


Imported  Parasites. 

Realizing  the  possibility  of  obtaining  relief  through  the  im- 
portation of  certain  parasites  which  serve  to  hold  the  gypsy 
and  brown-tail  moths  in  check  in  Europe  and  other  countries 
where  these  pests  occur,  the  officials  in  charge  of  suppressing 
these  insects  in  Massachusetts,  early  sought  the  cooperation 
of  the  Bureau  of  Entomology  at  Washington,  in  seeking 
parasites  abroad  and  in  introducing  them  into  this  country. 


20  Connecticut  Experiment  Station,  Bulletin    182. 

Consequently,  Dr.  L.  O.  Howard,  Chief  of  the  Bureau  of 
Entomology,  visited  Europe  in  1905,  and  enlisted  the  aid  of 
many  entomologists  there  in  collecting  and  sending  material 
to  the  laboratory  in  the  infested  section  of  Massachusetts. 
Either  Dr.  Howard  or  an  assistant  traveled  abroad  on  this 
work  each  summer  until  1910,  and  as  a  result  thousands  of 
packages  of  parasitized  material  were  received  from  all  the 
countries  where  the  gypsy  and  brown-tail  moths  are  found.  The 
parasites  were  reared  and  studied  in  captivity  and  the  primary 
parasites  separated  from  the  secondar}^  and  hyperparasites. 
Colonies   were   afterward   liberated. 

From  the  enormous  mass  of  material  collected  and  studied 
two  egg  parasites,  Telenomus  phalaenarum  Nees.,and  a  species 
of  Trichogramma  were  colonized  but  seem  to  be  unimportant 
in  controlling  the  brown-tail  moth.  From  hibernating  cater- 
pillars four  parasites  Pteromalus  egregiiis  Forst.,  Apanfeles 
lacteicolor  Vier.,  Meteorus  versicolor  W'esm.,  and  Zygoho- 
thria  nidicola  Towns.,  were  reared,  colonized,  and  have  now 
become  firmly  established  in  this  country.  The  last  named 
species  is  a  dipterous  or  two-winged  fly  of  the  family  Tachin- 
idse,  the  other  three  being  four-winged  flies  of  the  order 
Hymenoptera.  Several  Tachinid  flies  were  found  to  attack 
the  larger  caterpillars  and  one  of  them  Couipsiliira  concinnata 
Meig.,  is  now  established  and  bids  fair  to  be  of  some  value. 
Some  of  these  parasites  have  not  only  withstood  the  New 
England  winters  but  have  spread  a  considerable  distance  from 
the  point  where  they  were  liberated. 

Several  predatory  beetles  were  also  introduced,  and  a  large 
species  Calosoma  sycophanta  Linn.,  promises  to  be  of  con- 
siderable value. 

This  large-scale  introduction  of  parasites  is  the  most  impor- 
tant experiment  ever  made,  and  is  watched  with  interest  by 
entomologists  all  over  the  world. 

In  1912,  Mr.  A.  F.  Burgess  who  now  has  charge  of  the 
government  moth  work  in  New  England,  planted  a  colony 
of  Compsilura  concinnata  at  Putnam,  and  in  1913  another 
colony  at  Hartford.  This  species  has  not  yet  been  recovered 
in  Connecticut.  Apante/es  lacteicolor,  one  of  the  most  promis- 
ing of  the  hymenopterous  parasites  was  also  planted  in  a  colony 
of  1000  individuals  at  Putnam  in  1912  by  Mr.  Burgess.     In 


Control  Measures. 


21 


1913  it  was  recovered  from  nests  collected  by  Mr.  Caffrey  in 
five  towns,  viz.,  Thompson,  Woodstock,  Pomfret,  Stafford  and 
Somers,  the  last  named  town  probably  receiving  it  from  some 
point  in  Massachusetts  where  parasites  were  liberated.  In  1913 
additional  colonies  of  A.  lacteicolor  were  planted  in  nine  places 
viz.,  Hartford,  Suffield,  Mansfield,  Hampton,  Danielson,  Plain- 
field,  Griswold,  Norwich  and  Stonington.  This  parasite  is 
shown  in  figure  14. 

The  parasites   mentioned  above   can   do   no   harm  as   they 


'^^y,^ 


Fig.  14.     Apanteles  lacteicolor ,  a  promising  imported  parasite  which 

has  been  brought  into  Connecticut.     (After  Howard  and  Fiske, 

Bureau  of  Entomology,  U.  S.  Dept.  of  Agriculture.) 

attack  only  some  form  of  insect  life,  and  they  may  prove  a  real 
help  in  the  control  of  the  brown-tail  moth  pest. 


Control  Measures. 

As  both  male  and  female  moths  are  strong  fliers  the  spread 
of  the  species  cannot  be  prevented.  An  infestation  cannot 
be  eradicated  as  in  case  of  isolated  colonies  of  the  gypsy  moth. 
By  reducing  its  numbers  to  the  minimum,  however,  we  greatly 
lessen  the  danger  of  its  rapid  spread,  as  well  as  the  amount 
of  damage  which  it  may  do  by  defoliating  trees  and  by  afiflict- 
ing  people  with  brown-tail  rash. 


22 


Connecticut  Experiment  Station,  Bulletin    182. 


As  the  adults  are  attracted  by  lights  it  has  been  suggested 
that  by  means  of  trap-lights,  large  numbers  of  moths  might  be 
destroyed.  Several  careful  tests  have  been  made  with  such 
traps  and  though  large  numbers  of  moths  were  caught,  a 
large  proportion  of  them  were  males. 

Though  we  must  practice  control  measures  on  our  fruit 
trees  in  the  orchard  and  around  the  home,  w^e  must  rely  chief- 
ly on  natural  agencies  to  control  it  in  the  large  wooded  areas. 
The  principal  control  measures  are  removing  the  nests  in 
winter,  and  spraying  the  foliage  in  summer. 

Removing  Winter  Nests. 

After  the  leaves  have  fallen  the  nests  are  conspicuous  at 
the  ends  of  the  twigs  as  are  shown  in  figures  5  and  6,  and  bv 


Fig.  15.     Tree  pruners  for  clipping  off  nests. 


means  of  tree  pruners  can  easil}'  be  clipped  oft  and  burned. 
There  are  several  forms  of  tree  pruners  on  the  market,  three 
of  them  being  shown  in  figure  15.  Each  is  mounted  on  a  long 
pole  thus  enabling  one  to  reach  the  nests  without  climbing. 
(See  figure  16).  All  orchard  trees  and  all  fruit  trees  around 
the  buildings,  as  well  as  all  deciduous  trees  along  the  highways 
and  around  the  cultivated  fields  and  borders  of  the  woodlands 
should  be  examined  during  the  winter  months  and  the  nests 
removed. 

It  is  not  practicable  to  remove  the  nests  from  forests,  as 
they  cannot  be  detected  on  oak  and  beech  trees  which  hold 
their  leaves  through  the  winter.  Even  if  they  could  be  seen 
the  nests  are  out  of  reach  without  climbing,  and  the  cost  of 
this  is   prohibitive. 


Control  Measures. 


23 


If  the  ground  is  covered  with, snow,  it  is  easier  to  find  the 
nests  after  they  have  fahen  to  the  ground.  A  strong  paper 
bag  makes  a  good  receptacle  in  which  to  carry  the  nests  and 
on     reaching  the  house  the  bag  and  contents  should  be  put 


Fig.  16.     Workmen  cutting  off  brown-tail  nests;  this  tree  in  Hartford 
bore  220  nests. 


into  the  furnace  or  stove  where  there  is  a  hot  tire.  If  the 
nests  are  allowed  to  remain  in  a  warm  place  the  caterpillars 
will  emerge  and  crawl  about. 


24  Connecticut  Experiment  Station,  Bulletin    182. 

Spraying. 

It  is  not  easy  to  control  the  brown-tail  moth  by  spraying 
in  early  summer  because  the  caterpillars  often  devour  the 
young  leaves  as  fast  as  they  unfold,  and  there  is  no  leaf-sur- 
face to  poison.  If  the  foliage  is  thoroughly  sprayed  about 
August  1st,  the  young  caterpillars  v^^ill  be  killed  as  soon  as 
they  begin  to  feed  on  the  leaves.  This  is  perfectly  feasible 
on  trees  not  fruiting;  where  the  fruit  has  been  gathered  early; 
or  where  it  will  not  be  harvested  until  October,  as  with  winter 
varieties  of  apples  and  pears.  One  should  be  careful,  however, 
about  spraying  the  fruit  which  will  ripen  a  few  days  later. 

The  best  poison  for  spraying  is  lead  arsenate,  which  may 
be  used  at  the  rate  of  three  pounds  of  the  paste  form  to  a 
barrel.  If  the  dry  powder  is  used,  only  half  as  much  is 
needed. 

Local  or  Community  Effort. 

On  account  of  the  rash,  the  brown-tail  moth  is  perhaps  a 
greater  pest  than  on  account  of  its  damage  to  vegetation.  As 
the  moths  are  attracted  by  lights,  they  gather  in  villages  and 
cities,  and  around  the  homes  in  the  country.  In  thickly  set- 
tled communities  it  avails  little  for  one  resident  to  practice 
control  measures  if  his  neighbors  do  not.  Community  effort 
is,  therefore  necessary  in  order  to  achieve  the  best  results. 
Though  in  every  locality  there  are  individuals  who  will  keep 
their  own  trees  free  from  pests,  there  are  also  others  who, 
unless  compelled  to,  will  do  nothing  about  it.  State  laws  in 
New  Hampshire  and  Massachusetts  require  that  each  property 
owner,  before  a  certain  time,  remove  the  winter  nests  from  all 
trees  on  his  grounds.  If  he  fails  to  do  this,  the  town  or  city 
authorities  must  do  so,  and  the  cost  becomes  a  tax  which  is 
collected  from  the  property.  In  like  manner  all  municipal 
authorities  must  remove  the  nests  from  all  city,  or  town, 
property,  parks  and  along  the  public  highways.  Likewise 
if  this  is  not  done  by  a  certain  fixed  date  the  state  authorities 
may  order  it  done  at  the  expense  of  that  city  or  town. 

Legislation  Needed  in  Connecticut. 

Notwithstanding  the  control  work  which  has  already  been 
done  in  Connecticut  by  this  do[iartniont.  the  post  will  continue 


Summary.  25 

to  spread  and  will  gradually  cover  the  entire  state.  Nearly 
one-third  is  now  infested.  This  scouting  and  removing  of 
nests  cannot  be  continued  over  the  entire  area;  the  appropri 
ation  is  insufficient.  Even  were  it  adequate  for  the  purpose, 
it  probably  would  not  be  advisable.  The  owner  should  give 
some  attention  to  the  care  of  his  own  property.  Hence,  it 
will  probably  be  necessary  in  the  near  future  to  pass  laws  sim- 
ilar to  those  in  Massachusetts  and  New  Hampshire  requiring 
cities,  towns  and  individuals  to  remove  the  brown-tail  nests 
from  the  trees  and  shrubs  on  the  land  owned  and  controlled 
by  them. 


SUMMARY. 


DISTRIBUTION.  The  brown-tail  moth  was  probably  intro- 
-duced  accidentally  on  nursery  stock  at  Somerville,  Mass.,  more 
than  tw^enty  years  ago ;  it  w^as  brought  to  the  attention  of  ento- 
mologists in  1897.  It  has  long  been  known  as  a  pest  in  Europe 
w^here  it  causes  much  damage  to  fruit,  shade  and  forest  trees.  It 
also  occurs  in  Western  Asia  and  in  Northern  Africa. 

The  insect  has  spread  tow^ard  the  north  and  east  much  faster 
than  toward  the  south  and  west,  probably  going  in  the  direction 
of  the  prevailing  winds.  It  now^  covers  a  part  of  Nova  Scotia ; 
Southern  Maine ;  nearly  the  w^hole  of  Nev^^  Hampshire ;  almost 
the  entire  eastern  half  of  Vermont ;  all  but  the  extreme  western 
portion  of  Massachusetts ;  all  of  Rhode  Island ;  and  the  north- 
eastern portion  (about  one-third)  of  Connecticut.  It  was  first 
discovered  in  Connecticut  in  April,  1910;  within  a  few^  years  it 
w^ill  probably  extend  all  over  the  state. 

DAMAGE.  The  caterpillars  feed  upon  many  kinds  of  trees  and 
injure  them,  but  seem  to  prefer  fruit  trees.  Oak,  maple  and  elm 
are  next  attacked. 

The  hairs  of  the  caterpillars  break  off  and  blovs^  about ;  on 
coming  in  contact  w^ith  the  human  skin  they  cause  a  rash  or 
irritation  accompanied  by  intense  itching,  which  is  very  serious 
w^ith  some  persons. 

LIFE  CYCLE.  The  eggs  are  laid  on  the  under  side  of  a  leaf 
the  first  half  of  July,  in  masses  containing  from  200  to  400  eggs. 
They  hatch  inside  of  three  weeks  or  early  in  August  and  the 
young  caterpillars  skeletonize  the  leaves  from  the  upper  side, 
making  their  nest  in  September  at  the  tips  of  the  twigs.  They 
live  in  this  nest  through  the  winter,  emerge  and  feed  on  the  new 
leaves  in  the  spring,  becoming  fuU-grovs^n  about  the  middle    of 


26  Connecticut  Experiment  Station,  Bulletin    182. 

June.  They  then  transform  to  pupae  in  the  folded  leaves  and 
from  fifteen  to  twenty  days  later  the  moths  appear.  Both  sexes 
are  white  with  brown  hairs  at  the  end  of  the  abdomen  ;  they  fly 
at  night  ahd  sw^arm  around  electric  lights.  The  moths  have  a 
wing-expanse  varying  from  one  to  one  and  one-half  inches. 

NATURAL  ENEMIES.  A  fungus  in  moist  seasons  kills  many 
caterpillars.  Some  kinds  of  birds  devour  them  and  many  kinds 
eat  the  moths.  Many  parasites  have  been  imported  into  Massa- 
chusetts, from  Europe  and  other  countries,  and  some  of  them 
have  become  established.  Colonies  of  two  of  the  most  promising 
have  been  brought  into  Connecticut ;  one  of  them  has  been 
planted  in  ten  different  tow^ns  and  has  been  recovered  several 
miles  from  the  point  where  liberated. 

CONTROL  MEASURES.  Cutting  off  and  burning  the  nests  in 
w^inter,  and  spraying  the  foliage  in  August  with  lead  arsenate,  are 
the  best  methods  of  control  on  fruit  trees.  This  cannot  be  done 
in  the  forest. 

Community  effort,  especially  in  tow^ns  and  cities,  is  essential, 
and  probably  laws  similar  to  those  in  force  in  Massachusetts  and 
New  Hampshire  requiring  property  ovs^ners,  and  city  and  town 
officials  to  remove  nests  from  the  land  under  their  control,  vv^ill 
soon  be  needed  in  Connecticut. 


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